An approach to construction of chromosome map of rice.

通过将射线照射的花粉传给遗传标记种群，成功地诱导和选择了F^1中的许多染色体缺陷。正常品种为传粉者，花前一天对植株进行5KR辐射。得到2n = 23 + 1片段的植株19株，单体植株29株，显微镜下未检测到假显性植株。通过2n = 23 + 1片段杂交得到的F^1植株和二组体单体植株均为二组体，说明染色体缺陷没有遗传给下一代。我们还通过自交射线辐照三体植株或通过正常植株的传粉射线辐照花粉获得了3株2n = 24 + 1片段的带遗传标记的三体植株。获得单端三染色体组有很大的前景。花前1天辐照r-ay对诱导和选择易位纯合子效果显著，获得易位纯合子100余个。通过与正常植株的互易位杂合子初级三体杂交，得到了8种三级三体。本研究中发现的几种染色体交替现象对进一步的染色体定位和基因定位具有重要意义。我们成功地应用荧光染色技术对核仁染色体进行了鉴定。改进的粗线染色体制备方法使粗线染色体即使在固定的材料中也能出现完全伸展的粗线染色体。通过核型分析和长时间染色体分析，可以推测一些互易易位的染色体断点的位置。根据断点和遗传标记之间的连锁信息，我们还可以估计遗传标记的染色体位置或染色体方向，如染色体1、3和11的连锁图的臂位。少

Many chromosomal deficiencies were successfully induced and selected in F^1 obtained by pollinating r-ray irradiated pollens to genetic marker stocks. Normal varieties were pollinators and the plants themselves were irradiated r-ray (5KR) one day before anthesis. We obtained 19 plants of 2n = 23 + 1 fragment, 29 monosomic plants, and many plants which showed pseudodominance but no deficiency detected in microscopic level. All of the F^1 plants derived from crossing the 2n = 23 + 1 fragment and monosomic plants with disomics were all disomics, indicating that the chromosome deficiency was not transmitted to the next generation. We also obtained three plants of 2n = 24 + 1 fragment through the selfing r-ray irradiated trisomic plants or through the pollinating r-ray irradiated pollens of normal plants to trisomics with genetic markers. There was much prospect to get monotelotrisomics. Irradiation of r-ay one day before anthesis was very effective for inducing and selecting reciprocal tra … More nslocation and more than one hundred reciprocal translocation homozygotes were bred. Eight types of tertiary trisomics were also derived from crossing reciprocal translocation heterozygote primary trisomics with normal plants. The several kinds of chromosome alternations developed in this study would much contribute further chromosome mapping and gene mapping.We successfully applied fluorescent staining technique with Chromomycin A to identify nucleolus chromosomes. Modified methods of pachytene chromosome preparation made it possible to appear fully spreading pachytene chromosomes even in fixed materials.It was possible to Infer the chromosomal location of breakpoint of some reciprocal translocations through karyotype and pachytine chromosome analysis. Based on the linkage informations between the breakpoints and genetic markers, we also could estimate chromosomal location of the genetic markers or chromosomal orientation such as arm location of linkage maps regarding chromosomes 1, 3 and 11. Less